Method and means for pumping air in air balanced pumping units



Jan- 18, 1949. E. w. PATTERSON ET AL METHOD AND MEANS FOR PUMPING AIR IN AIR BALANCED PUMPING UNITS Filed Oct. 9, 1944 L VVZJVTOR fps/m 1/4 p47f5050/K ATTORNEY;

Patented Jan. 18, 1949 METHOD AND MEANS FOR PUMPING AIR IN AIR BALANCED PUMPING UNITS Edgar W. Patterson and Clifford D. Spracher, Downey, Calif.; said Spracher assignor to said Patterson Application October 9, 1944, Serial No. 557,870

17 Claims.

This invention relates to counterbalanced well pumping mechanism, and particularly pertains to a method and means for pumping air in air balanced pumping units.

In pumping units, such for example as well pumpin units in which a walking beam operates a string of pump rods, it is necessary to provide means for counterbalancing the apparatus to compensate for variation in load upon the opposite strokes of the pump mechanism. In some instances a counterbalance weight is provided for this purpose, while in other instances a fluid counterbalance is provided, such as disclosed in U. S. Patent No. 2,293,915 issued August 25, 1942, to Edgar W. Patterson. In such apparatus it is desirable to provide means for pumping air into the fluid counterbalance systern and into the main air tank forming a part of the air-balanced pumping unit. In the type of pumping equipment disclosed in the aforementioned patent a main balance cylinder of the double acting type is employed, the upper portion of which cylinder can be utilized for the purpose of supercharging an air compressor constantly while the pumping unit is in normal operation by simply connecting a suitable pipe between the intake of the compressor and the discharge from the compressor portion of the balance cylinder. Therefore, this connection may be arranged to discharge air directly into the main operating compressor cylinder of an air balanced pumping unit. This method of supercharging the compressor constantly would not require the use of any small air receiver because the compression of air above the piston within a double acting counterbalance cylinder would take place synchronously with the upstroke or intake stroke of any reciprocating compressor which might be operated from the oscillation of a walking beam, such as is disclosed in U. S. Patent No. 2,293,916 issued August 25, 1942, to Edgar W. Patterson. Attention is also directed to the general type of air compressor shown in U. s. Patent Reissue No. 20,287 issued to Edgar W. Patterson on March 9, 1937, and in which structure it would not be necessary to employ an auxiliary air receiver in the event a constant discharge air compressor is used and would make no particular difference whether the counterbalance cylinder was either double or single-acting, except that in case a single-acting counterbalance cylinder is used the air compressor could only be supercharged while the main control valve is closed and at which time the pumping unit would not be functioning in normal operation.

The foregoing specific example of a method and means for supercharging an air compressor constantly or intermittently in a counterbalancing system have been made to emphasize the desirability of providing simple means for supercharging the compression system without the use of an auxiliary compressor.

It is desirable to provide means manually and optionally controlled for introducing atmospheric air into the counterbalance system of a pumping unit, and when desired to be able to supercharge the main operating air compressor which furnishes air under pressure to the unit.

It is the principal object of the present invention, therefore, to provide a method and means of constantly pumping air into the fluid counterbalance system of a pumping unit incident to the pumping operation by the use of simple apparatus which may be controlled by manual operation to supercharge the air compressor and to maintain a desired uniform degree of fluid pressure Within the system completely under the control of the operator.

The present invention contemplates a pumping unit, inclmuding a pneumatic counterbalance which may employ a single or double-acting balancing cylinder operating in conjunction with an auxiliary compressor by a method whereby the unit may be manually controlled to super charge the compressor and to continuously supply air to the system for counterbalancing purposes, at a substantially constant pressurev value. The invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a'view in side elevation showing the structure of Fig. 2 and the apparatus with which the present invention is concerned and indicating the relation of parts of the counterbalancing apparatus and compressor.

Fig. 2 is a viewin end elevation showing a pump mechanism and indicating generally the construction and arrangement of the counterbalancing cylinder and one form of the present invention.

Fig. 3 is an enlarged view in vertical section and elevation with parts broken'away showing a double-acting compressor cylinder and an alternate arrangement of piping connections thereto, and indicatin the piping in a common transverse plane for sake of convenience.

Fig, 4 is a View in side elevation showing the structure of Fig. 3 and the compression cylinder with the fluid circulating conduits connected the air compressor disclosed in Fig. and indi-- eating particularly the valve and pipe connections thereto.

Referring more particularly to Figs. 1 and? v of the drawings, in indicates a base structure which is here shown as made from suitablestruc-. tural steel elements. Rigidly secured to the upper face of the base structure and near one end thereof is a pair of structuralelements forming a samson post ii. A king pin I2 is carriedat the upper end of the samson post H and pivotally supports a walking beam 13. The walking beam is vertically reciprocated by a driving unit M which carries a crankdisc [5. The discs are fitted withcrank pins 16 engaging the lower ends of pitman rods H. The upper ends of pitman rods l'lare pivoted to the walking beam 13 at a point intermediate itsends upon a pin H3. The oscillation'of the walking beam I3 is counterbalanced by a balance cylinder I9 within which a piston 20 reciprocates. The upper end of the balance cylinder 1 9 is pivoted to the walking beam upon a pin 2! disposed between the pitman rod pin 1 8 and the free end of the walking beam. The balance cylinder i9 is closed at its upper end and maybe open at its lower end, as shown in Fig. 2 of the drawings. The piston 20, which is mounted therein, is carried upon a tubular pis-' ton rod I 22 through which communication is established with the compression chamber 23 in the head of the cylinder. The piston rod 22 extends downwardly and is connected to a transverse T-end 24 which-is mounted in a pair of spaced bearing blocks 25 carried upon a base frame structure 26 which extends around an air reservoir 21. The air reservoir is in the form of atank extending with its longitudinal axis horizontal, :and is here indicated as having its axis in the Vertical plane of the axis of the balance cylinder 19. The T-shaped fitting 24 at the lower end of the piston rod has a passageway through one leg thereof communicating with a passageway 22', which extends within and longitudinally of the piston 22. The passageway in the member -24 is provided with a pipe connection 28 which extends horizontally and connects at its outer end with a T-pipe fitting 29. One horizontal leg of the T-fitting 25) connects with an intake check valve 30. The other horizontal leg connects with a'discharge check valve 3!. A vertical leg of the T-fitting 29 connects with a main air control valve 32 which is designed to be operated manually. A pipe 33 is connected to the valve 32 and extends downwardly to engage the vertical leg of a T-fitting 34. One horizontal leg of the T-fitting 34 is provided with a pipe 35 which establishes communication with the air reservoir .21. The other horizontal leg of the T-fitting at is provided with a check valve 36 which permits fluid to pass through the valve toward the T-fitting 34 and interrupts the flow of fluid in the opposite direction. 'A conduit 31 is connected to the-opposite side of the check valve36 and connects with a T-fitting 38. One leg of this fitting connects with a T-fitting 39 by means of a pipe 40. ThegT-fitmanually operated valve 60.

ting 39 is connected to the check valve3l by a pipe The opposite leg of the T-fitting 39 is connected to a manually controlled valve 42 which opens to atmosphere.

The T-fitting 36 is provided with a conduit 63 connecting with a surge tank 44. The surge tank has a capacity several times greater than the capacity; of the balance cylinder is so that air may be delivered to an air compressor at sub stantially constant pressure. At the opposite'side of the point of connection of the conduit 43 with the surge tank 54 and near the bottom of the surge tank M is a pipe 45. This connects with a manually operable shut-01f valve 46 which is attached .to a pipe 47.. The pipe 11 connects with a check valve 48 through which air may pass to a pipe 39 connected to the bottom of an auxiliary air compressor cylinder 50. This air compressor is of the single-acting type and 'is provided with a piston 5! connected to a pitman rod52. The pitmanrod52 isconnectedpivotally to :the walking beam l3 upona pivot 53 which'is disposedat a point between the king pin. lZ-andthe pivot pin l8. ,2 r q v In the form of the inventionshqwn in Fig. 3 of the drawings a double-acting balance cylinder 33' is provided with ;a pipe connection 54 receiving a T fitting 55 to which armanually operated valve 56 is attached. A pipe 51 connects the T-fitting ii5 to a T-fitting 58. One leg of the T-fitting 58 carries an intake check valve 59,

and another leg of the fitting is connected to a The valve Bilgas shownin Figs. 3 and 4 of-the drawings, isprovided with a pipe 6! which connects with a secondary discharge check valve 62. The secondary discharge check valve 62 is fitted with apipe 63 directly connecting with the balance cylinder l9 at a point below the lower end'of the stroke of piston 28. In the particular form of invention shown in Fig; 3;,it:will-be noted that the cylinder and piston are invertedso that piston rod; 2 2i extends upwardly and. is connected to the walking beam; [3 while the cylinder I9 is pivotally mounted within the bearing blocks 25 and is fitted with the outlet connection 2% previously described. The remaining construction of the compressor-and circulating system of the structure in Fig. 3 is the same as that shown in Fig. 1 of the drawings, with the exception that a manually operated cut-oi? valve Bflis interposed inthe length of the conduit 43 whichconnects the -T-fitting .38 with the surge tank 44, as shown in Fig. 4 of the drawings. It will also be noted by an-examination of this figure of the drawingsthat the manually operatedvalve 46, whichhad been shownin Fig. 1 as interposed between the pipes 45 and 47, has been eliminated and a' conduit 65' has been provided to-establish a connectioniwith the check valve 48.

"By reference to Figs..3 .and 4, it will be seen that the upper end-of thecylinder l9' -is fitted with anfloutlet pipe 66 which connects with a check valve 151. The check valve 6'! allows air to -pass frorn'the cylinder i9 but not to enter the cylinder through thepipe 6K5. Apipe 68 is .con-' nected to the outside of the check valve andcarriesia manually operated-cut-oii valve 69. A pipe lilis attached ad-the cut-off valve 69 and has. a-flexible conduit 10' secured to it; This con duitis connected-with the upper end of the surge tanked. 1 i

The auxiliary aircompressor 50 1s shown in Figs. 5 ands oftth'e drawings. The compression head; .ofthe' auxiliary: air compressor 50 is provided with a pipe connection H which leads to a check valve 12. The check valve 72 is connected with a pipe 13 attached to the main air reservoir and a pressure indicating gauge 14. The valve [2 permits flow of fluid from the compressor 59 to the main air receiver and gauge. Also connected to the compression head of the auxiliary compressor 50 is a pipe '15. At the outer end of this pipe a check valve it is provided. The valve 76 permits the entry of air into the auxiliary compressor 5B and prevents a reverse flow of air therethrough.

t the present time the most useful application of the invention is by operating the single-acting auxiliary compressor 50, as is employed on most air-balanced units in synchronous operation with a reciprocating air-balance cylinder and compressor, such as indicated at 19, and by which arrangement the pumping rate of air into the main air receiver of a present-day type of airbalance pump unit will be greatly increased. It is to be understood in explaining the present invention that the combination of the valves shown in Fig. l of the drawing and there indicated by the numerals 3t, 3!, 32 and 35, and the conduits connecting them with the balance cylinder l9 and air receiver 27, involve a method of utilizing the balance cylinder H) of an air-balance pump unit as a primary compressor for initially charging the main air receiver 21 of an air-balanced pumping unit with air under a pressure, which in all probability will be less than the maximum pressure required for ideal operation of the unit. This method and the specific structure used in practising it is shown and described in U. S. Patent No. 2,293,915 issued to Edgar W. Patterson on August 25, 1942, and also in connection with a single-acting balance cylinder shown and described in U. S. Patent No. 2,218,216 issued to Charles M. OLeary on the 15th day of October, 1940.

The present invention is concerned with a method and means for greatly increasin the output capacity of any type of compressor as shown in patents mentioned hereinbefore, and accmplishes this by connecting the balance cylinder of either the double or single acting type with the intake of a compressorwhich is arranged to discharge air under pressure direct to the main air receiver 2'! of the pumping unit. This result is accomplished while either the upper or lower compression spaces of the balance cylinder are being utilized as a compressor and not for counterbalancing purposes.

Before explaining the operation of the invention a thorough technical understanding of the advantages to be gained by the use of this construction is desirable. This may be had from an analysis of the mathematical formulae governing the isothermal compression of air or gases, wherein:

and wherein P1=origina1 absolute pressure in lbs. V1=original volume in cubic inches P2=second absolute pressure V2=second volume A typical example of an actual problem would be as follows:

Assume a pumping unit to be operating at 20 revolutions, or strokes, per minute while the process of pumping up air to say 200 pounds per square inch in the main air receiver is taking place. Assume that a compressor of 5-inch diameter by 7-inch stroke is being used for the purpose. Therefore, the displacement in cubic inches per minute equals cubic inches of air per minute being compressed from 0 gauge pressure (14.7 absolute pressure) to (214.7 lbs. absolute) or 200 lbs. gauge pressure. And by the same formula wherein we utilize the balance cylinder as a primary compressor for superchargin the same compressor as cited above to say lbs. per square inch, We have cubic inches per minute of air compressed to 200 lbs. gauge pressure per square inch or 7.8 times as much air being compressed and discharged into the main air receiver as was formerly discharged by the same compressor wherein this improved method was not employed. Therefore, it is perfectly obvious to anyone that if it required 2 hours to charge the main air receiver of a unit up to 200 lbs. by the old method, it would require but 15 /2 minutes to do the same thing by the use of this improved method.

With reference to the accompanying drawings, the construction of the unit embodying the invention and the method of practising the in" vention may be explained as follows:

By reference first to Figs. 1 and 2, it will be assumed that the pumping unit is idle and that all air pressure in the unit is at zero. First, the unit is set in motion at the normal revolutions per minute and the main air control valve 32 is closed. This will cause the main balance cylinder l9 to function automatically as a compressor by drawing air into the unit through the intake valve 30 and to discharge this air on the succeeding down-stroke of the balance cylinder i9 through pipes 28, 35 and 31 and the check valves 3! and 36. The air then passes into the main air receiver 21 by Way of the pipe 35. It should be pointed out that during this period air will be trapped in the small surge tank or receiver 44 after it passes through the check valve 3! and while it is prevented from escaping to the compressor for the time being by manually operated valve 46. This action will take place during the same period and under the same pressure as the air then being discharged into the main receiving tank 27. By this method the air pressure in the main receiver 21 will be built up quickly to approximately 100 pounds pressure per square inch. It will not be possible to develop a pressure greatly in excess of 100 pounds per square inch because the clearance volume or space remaining in the balance cylinder I9 when it has completed its down or compression stroke is not and cannot be reduced to a smaller volume conveniently. Therefore, within a comparatively short period of operation the pressure within the main air receiver 21 will be equal to the maximum pressure being developed by the balance cylinder I9 while it is functioning as a compressor. Under this condition no more air will be discharged into the main air receiver 2'. and theair entrapped within the balance cylinder will be re-compressed on each down-stroke and expanded durin each up-stroke of the walking beam without being displaced.

auxiliary compressor unit including a cylinder and piston and interposed between a fixed support and the walking beam whereby relative movement between said parts may take place as the walking beam oscillates, an air conduit leading to the balance cylinder, an inlet check valve in communication therewith whereby atmospheric air may be drawn into the balance cylinder, a connecting air conduit between said first named conduit and the auxiliary compressor cylinder, a backflow check valve interposedv at a point in said conduit, a receiving tank, a discharge flow conduit from the auxiliary compressor to the receiving tank, a backflow check valve interposed at a point therein, and a pipe connection between the connecting conduit and the receiving'tank and a backfiow check valve therein.

5. The structure of claim 4 including a manually operated cut-ofi valve interposed in the connecting conduit between the auxiliary compressor and said pipe connection.

6. The structure of claim 4 including a manually operated cut-ofi valve interposed in the connecting conduit between the auxiliary compressor and said pipe connection, and a surge tank interposed in the connecting conduit at a point between said pipe connection and said manuall" controlled valve.

7. The structure of claim 4 including a manually operated cut-ofi valve interposed in the connecting conduit between the auxiliary compressor and said pipe connection, and an atmospheric air inlet connection to the auxiliary compressor cylinder and a backflow check valve therefor.

8. A counterbalance for a well pumping unit having a power actuated walking beam, said counterbalance including a double-acting balancing unit having a cylinder closed at its opposite ends and a piston reciprocating therein, one of said elements being adapted to be secured to the walking beam and the other to a fixed support, an auxiliary compressor including a cylinder and a piston, one of said elements being adapted to be attached to the Walking beam and the other element to a fixed support, whereby said balance unit and auxiliary compressor will operate simultaneously, an air receiver, a conduit establishing communication between one end of said balance cylinder and the air receiver, a conduit establishing communication between the auxiliary com pressor and the air receiver, atmospheric air inlets to both ends of said balance cylinder, conduits from both ends of said balance cylinder communicating with the auxiliary compressor, and valve means manually operable optionally directing air under compressor from either end of said balance cylinder to said auxiliary compressor.

9. The structure of claim 8 including means for optionally opening either end of said balance cylinder to the atmosphere.

10. The structure of claim 8 including a surge tank interposed between the auxiliary compressor and the conduits leading from both ends of the balance cylinder.

11. A well pumping jack, comprising a power driven walking beam, a pneumatic counterbalance unit associated therewith and comprising a balance cylinder and a piston interposed be tween a fixed support and the walking beam, said parts having relative movement as the beam oscillates, a conduit through which air may pass to the counterbalance unit, a check valve at a point in said line, an air receiver, a conduit connecting the counterbalance unit and said air receiver,

10 a valve in said line whereby the counterbalance unit may be isolated from the air receiver, a second conduit connected with said counterbalance unit, a valve therein whereby the counter- 3 balance unit may be vented to atmosphere, a

conduit connecting with said last named conduit and the air receiver and bypassing the first named valve, a check valve in the conduit carrying the valve which may be open to atmosphere, and a check valve in the bypass conduit permitting the flow of air to the air receiver.

12. A counterbalance unit for well pumping jacks including a balance cylinder and piston adapted to be interposed between a fixed support and a walking beam of a pump jack, whereby relative movements between said cylinder and piston may take place as the walking beam oscillates, an auxiliary compressor, a pipeline between the compression chamber of the balance cylinder and said auxiliary compressor, a surge tank interposed at a point in said pipeline, an air receiver, a pipe connection from the portion of the pipeline between the balance cylinder and the surge tank to the air receiver, a check valve interposed in said pipe connection to permit air to flow from the balance cylinder, a check valve interposed in the air receiver connection to permit air to flow into the air receiver, a check valve in the portion of the connecting line from the surge tank to the auxiliary compressor permitting air to fiow to the compressor, and a manually operated valve in the same portion of said line to open and close the line.

13. In combination with a compressor unit for pump jacks including a balance cylinder and a piston adapted to be interposed between a fixed support and the walking beam of said jack, whereby relative movement may take place between said members as the walking beam oscillates, and an air receiver connected with said balance cylinder; an auxiliar compressor including a cylinder and piston adapted to be interposed between the walking beam and the fixed support to have relative movement as said beam oscillates, a conduit through which fluid may flow from the balance cylinder to the compressor cylinder, a check valve at a point therein, a conduit through which air may fiow from the auxiliary compressor to the air receiver, a check valve,

therein, and a conduit leading from the atmosphere to the auxiliary compressor and a check valve therein, whereby air which has been compressed in the balance cylinder will be delivered to the auxiliary compressor and will be recompressed therein as it is forced into the air receiver.

14. The structure of claim 13 including a surge tank in the line of air flow between the balance cylinder and the auxiliary compressor.

15. The structure of claim 13 including a conduit directly connecting the balance cylinder with the air receiver, a manually operated valve in said conduit for establishing or interrupting flow therethrough, and a manually operated valve in the conduit connecting the balance cylinder and the auxiliary compressor for establishing and interrupting air therethrough.

16. In combination with an air-balanced pump jack having a walking beam, an air counterbalance unit, and an air receiver; an auxiliary air compressor comprising a fixed cylinder, a piston adapted to be connected to the walking beam and reciprocating within said fixed cylinder as the walking beam of the pump jack oscillates whereby air will be compressed in the fixed cylinder, an intake pipe establishing communication between the air-balanced ipump jack and. the auxiliary compressor cylinder, a check valve at a point along said intake pipe, a communicating pipe between the auxiliary compressor cylinder and an air receiver of the counterbalance unit, a check valve at a point along the connecting pipe, an air pipe establishing communication between said auxiliary compressor cylinder and the atmosphere, and a check valve therein. 7

17. In combination with a counterbalance'cyl inder, a piston and air receiver of an air counterbalance ipump jack, an auxiliary compressor unit comprising a piston and fixed cylinder adapted to. have relative movement to each other asthe walking beam of the pump jack oscillates, a conduit connecting the air receiver and the, air

counterbalance cylinder, a manually operated cut-off valve therein, a conduit connecting the counterbalance cylinder and the cylinder ofthe auxiliary compressor, a manually operated outoif valve therein, a bypass conduit, a check valve REFERENCES CITED The following referencesare of record in the fil of this patent:

UNITED STATES PATENTS I I Date Number Name 2,148,638 Patterson Feb. 28, 1939 2,169,815 Patterson Aug. 15,1939 2,243,117 Patterson 1 May 27; 1941 2,291,499 Penick July'28, 1942v 2,293,915 Patterson Aug; 25, 1942 2,293,916

Patterson Aug. 25, 1942 

